wicked_pdf not working in production server

Locally It works without any error but when I try to generate the PDF on the server it trows:

RuntimeError (Failed to execute: ["/usr/local/bin/wkhtmltopdf", "-q", "file:////tmp/wicked_pdf20180531-994-1x8fbfn.html", "/tmp/wicked_pdf_generated_file20180531-994-1vidmtk.pdf"] Error: PDF could not be generated!

Command Error: /usr/bin/env: ruby: No such file or directory ):

Here's what's on my_controller.

pdf=WickedPdf.new.pdf_from_string(render_to_string('disc_bill',:layout=>false))
  save_file = Rails.root.join("public","bill.pdf")
  File.open(save_file, 'wb') do |file|
    file << pdf
  end

And in my Gemfile

gem 'wicked_pdf', '~> 1.1' gem 'wkhtmltopdf-binary', '~> 0.12.3.1'